In managed pressure borehole operations, the wellbore pressure is controlled using a closed annulus and a mechanism for regulating pressure in the annulus. The annulus may be closed during drilling through use of a rotating control device (RCD) or pressure control device (PCD), which seals the drill pipe as the wellbore is being drilled. Efforts to improve pressure and flow control during managed pressure borehole operations are ongoing.
It should be understood, however, that the specific embodiments given in the drawings and detailed description thereto do not limit the disclosure. On the contrary, they provide the foundation for one of ordinary skill to discern the alternative forms, equivalents, and modifications that are encompassed together with one or more of the given embodiments in the scope of the appended claims.